Expansion of non-native plant Flaveria bidentis (L.) Kuntze driven by a range of factors leading to patchy distribution patterns.

Given the growing concern over the ecological impacts of non-native species, exploring these species' expansion edge and distribution patterns and their driving factors is important for developing suitable management measures. Flaveria bidentis (L.) Kuntze, a non-native plant that was introduced to China in the 1990s, has spread from southern Hebei Province, where it first took root, to the surrounding regions and has become one of the most notorious invasive weeds in northern China. Based on 15 years (2006-2021) of extensive field investigations, the spatial distribution of sampling and occurrence points were mapped in the recently expanded region of F. bidentis' population. Then, nearest neighbor analysis is used to characterize the spatial pattern differences between samplings and occurrences. An exponential decay function was used to elucidate the driving factors contributing to the presence and absence of F. bidentis. Our results demonstrated an effective random sampling setup, a heterogeneous spatial distribution of F. bidentis, and a multi-regional independent aggregation distribution pattern (p < .01). There were significant spatial correlations between the aggregation areas of plant occurrence points and the locations of roads and construction sand distribution centers. These findings suggest that human activities involving major roads and construction sand distribution centers were driving factors contributing to this long-distance dispersal and spatially discontinuous distribution patterns. The presence of these patchy distribution patterns has important implications for ongoing efforts to manage populations of non-native species.

Reliable and rapid identification of glyphosate-resistance in the invasive weed Amaranthus palmeri in China.

BACKGROUND: Glyphosate-resistant invasive plants, including Amaranthus palmeri S. Watson, have greatly challenged management of new invasions. Elucidating their glyphosate resistance levels rapidly and accurately will better inform management strategies. Quantitative real-time PCR (qPCR) has been used to identify glyphosate resistance in A. palmeri by detecting gene copy numbers of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme inhibited by glyphosate. However, qPCR can only indirectly determine copy numbers because it requires a calibrator sample; it also lacks standardization, thus limiting its usefulness. Droplet digital PCR (ddPCR) is a new method to detect copy number directly and precisely. We evaluated ddPCR as a tool to determine glyphosate-resistance level while using qPCR and glyphosate dose response (GDR) assays as reference technologies to compare performance and efficiency between methods. RESULTS: We identified seven susceptible and seven resistant populations of A. palmeri using the GDR assay. Resistant levels detected by qPCR and ddPCR were generally consistent with the GDR results. Although detected values obtained by qPCR and ddPCR were highly correlated (R2  = 0.94), ddPCR results had a lower proportion of non-ideal values (36%) with better accuracy (100%) and specificity (100%) than those of qPCR results. CONCLUSIONS: Our findings demonstrate that ddPCR offers improved accuracy and specificity in detecting EPSPS gene copy numbers and is a robust and rapid method for glyphosate-resistance identification in A. palmeri. Our research is the first to measure glyphosate resistance in A. palmeri by ddPCR assay and will shed light on future applications of ddPCR in identifying herbicide resistance in other invasive weeds. © 2022 Society of Chemical Industry.

Roles of Lung Ultrasound Score in the Extubation Failure From Mechanical Ventilation Among Premature Infants With Neonatal Respiratory Distress Syndrome.

Objective: To investigate the predictive value of lung ultrasound score (LUS) in the extubation failure from mechanical ventilation (MV) among premature infants with neonatal respiratory distress syndrome (RDS). Methods: The retrospective cohort study was conducted with a total of 314 RDS newborns who received MV support for over 24 h. After extubation from MV, infants were divided into extubation success and extubation failure groups. Extubation failure was defined as re-intubation within 48 h after extubation. Univariate and multivariate logistic regression analyses were used to identify the predictors of the extubation failure. The predictive effectiveness of the combined model and LUS in the extubation failure was assessed by receiver operating characteristic curve, area under curve (AUC), and internal validation. Results: 106 infants failed extubation from MV. The combined model for predicting the extubation failure was performed according to the predictors of gestational age, body length, birth weight, and LUS. The AUC of this combined model was 0.871 (sensitivity: 86.67%, specificity: 74.31%). The AUC of LUS was 0.858 (sensitivity: 84.00%, specificity: 80.69%), and the cutoff value was 18. There was no statistical difference in the predictive power between the combined model and LUS (Z = 0.880, P = 0.379). The internal validation result showed that the AUC of LUS was 0.855. Conclusions: LUS presented a good ability in predicting the extubation failure among RDS newborns after MV.

SEMA3A protects against hyperoxia-induced lung injury in a bronchopulmonary dysplasia model of newborn rat by inhibiting ERK pathway.

BACKGROUND: Hyperoxia induces lung injury through lung inflammation in premature infants, leading to bronchopulmonary dysplasia (BPD). Semaphorin 3A (SEMA3A) participates in diverse biological processes, including cell migration, angiogenesis, and inflammation. The effect of SEMA3A on hyperoxic lung injury of neonatal rats with BPD was investigated in this study. METHODS: Neonatal rats with BPD were established through hyperoxia treatment. Hematoxylin-eosin staining was used to evaluate histopathological analysis in lung tissues. SEMA3A expression was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assay. Adeno-associated virus (AAV)-mediated over-expression of SEMA3A (AAV-SEMA3A) was administrated into hyperoxia-induced rats, and apoptosis was evaluated by TUNEL staining. Levels of inflammatory cytokines were investigated by enzyme-linked-immunosorbent serologic assay (ELISA). RESULTS: Hyperoxia-induced histopathological changes in lung tissue reduced alveolar number and enhanced alveolar interval and alveolar volume. SEMA3A was downregulated in lung tissue of hyperoxia-induced rats. AAV-SEMA3A injection attenuated hyperoxia-induced cell apoptosis in lung tissues by increasing Bcl-2 and decreasing Bax and cleaved caspase-3. Moreover, the enhanced levels of Interleukin (IL)-1ß, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor-α (TNF-α) in hyperoxia-induced rats were restored by AAV-SEMA3A injection by the downregulation of nuclear factor kappa B (NF-κB) phosphorylation. AAV-SEMA3A injection also ameliorated histopathological changes in lung tissues of hyperoxia-induced rats by increasing the number of radial alveolar count and decreasing the volume of mean linear intercept. Besides, the protein expression levels of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) phosphorylation were reduced in hyperoxia-induced rats post-AAV-SEMA3A injection. CONCLUSION: Ectopical expression of SEMA3A suppressed hyperoxia-induced apoptosis and inflammation in neonatal rats, and ameliorated the histopathological changes through inactivation of ERK/JNK pathway.

SEMA3A protects against hyperoxia-induced lung injury in a bronchopulmonary dysplasia model of newborn rat by inhibiting ERK pathway

Background Hyperoxia induces lung injury through lung inflammation in premature infants, leading to bronchopulmonary dysplasia (BPD). Semaphorin 3A (SEMA3A) participates in diverse biological processes, including cell migration, angiogenesis, and inflammation. The effect of SEMA3A on hyperoxic lung injury of neonatal rats with BPD was investigated in this study. Methods Neonatal rats with BPD were established through hyperoxia treatment. Hematoxylin-eosin staining was used to evaluate histopathological analysis in lung tissues. SEMA3A expression was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assay. Adeno-associated virus (AAV)-mediated over-expression of SEMA3A (AAV-SEMA3A) was administrated into hyperoxia-induced rats, and apoptosis was evaluated by TUNEL staining. Levels of inflammatory cytokines were investigated by enzyme-linked-immunosorbent serologic assay (ELISA). Results Hyperoxia-induced histopathological changes in lung tissue reduced alveolar number and enhanced alveolar interval and alveolar volume. SEMA3A was downregulated in lung tissue of hyperoxia-induced rats. AAV-SEMA3A injection attenuated hyperoxia-induced cell apoptosis in lung tissues by increasing Bcl-2 and decreasing Bax and cleaved caspase-3. Moreover, the enhanced levels of Interleukin (IL)-1β, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor-α (TNF-α) in hyperoxia-induced rats were restored by AAV-SEMA3A injection by the downregulation of nuclear factor kappa B (NF-κB) phosphorylation. AAV-SEMA3A injection also ameliorated histopathological changes in lung tissues of hyperoxia-induced rats by increasing the number of radial alveolar count and decreasing the volume of mean linear intercept. Besides, the protein expression levels of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) phosphorylation were reduced in hyperoxia-induced rats post-AAV-SEMA3A injection (AU)

Transcriptome analysis of gene expression changes upon enzymatic dissociation in skeletal myoblasts.

Single-cell RNA-sequencing analysis is one of the most effective tools for understanding specific cellular states. The use of single cells or pooled cells in RNA-seq analysis requires the isolation of cells from a tissue or culture. Although trypsin or more recently cold-active protease (CAP) has been used for cell dissociation, the extent to which the gene expression changes are suppressed has not been clarified. To this end, we conducted detailed profiling of the enzyme-dependent gene expression changes in mouse skeletal muscle progenitor cells, focusing on the enzyme treatment time, amount and temperature. We found that the genes whose expression was changed by the enzyme treatment could be classified in a time-dependent manner and that there were genes whose expression was changed independently of the enzyme treatment time, amount and temperature. This study will be useful as reference data for genes that should be excluded or considered for RNA-seq analysis using enzyme isolation methods.

Epigenetic effects induced by the ectopic expression of Pax7 in 3T3-L1.

Although skeletal muscle cells and adipocytes are derived from the same mesoderm, they do not transdifferentiate in vivo and are strictly distinct at the level of gene expression. To elucidate some of the regulatory mechanisms underlying this strict distinction, Pax7, a myogenic factor, was ectopically expressed in 3T3-L1 adipose progenitor cells to perturb their adipocyte differentiation potential. Transcriptome analysis showed that ectopic expression of Pax7 repressed the expression of some adipocyte genes and induced expression of some skeletal muscle cell genes. We next profiled the epigenomic state altered by Pax7 expression using H3K27ac, an activating histone mark, and H3K27me3, a repressive histone mark, as indicators. Our results show that ectopic expression of Pax7 did not result in the formation of H3K27ac at loci of skeletal muscle-related genes, but instead resulted in the formation of H3K27me3 at adipocyte-related gene loci. These findings suggest that the primary function of ectopic Pax7 expression is the formation of H3K27me3, and muscle gene expression results from secondary regulation.

Genome-wide analysis of chromatin structure changes upon MyoD binding in proliferative myoblasts during the cell cycle.

MyoD, a myogenic differentiation protein, has been studied for its critical role in skeletal muscle differentiation. MyoD-expressing myoblasts have a potency to be differentiated with proliferation of ectopic cells. However, little is known about the effect on chromatin structure of MyoD binding in proliferative myoblasts. In this study, we evaluated the chromatin structure around MyoD-bound genome regions during the cell cycle by chromatin immunoprecipitation sequencing. Genome-wide analysis of histone modifications was performed in proliferative mouse C2C12 myoblasts during three phases (G1, S, G2/M) of the cell cycle. We found that MyoD-bound genome regions had elevated levels of active histone modifications, such as H3K4me1/2/3 and H3K27ac, compared with MyoD-unbound genome regions during the cell cycle. We also demonstrated that the elevated H3K4me2/3 modification level was maintained during the cell cycle, whereas the H3K27ac and H3K4me1 modification levels decreased to the same level as MyoD-unbound genome regions during the later phases. Immunoblot analysis revealed that MyoD abundance was high in the G1 phase then decreased in the S and G2/M phases. Our results suggest that MyoD binding formed selective epigenetic memories with H3K4me2/3 during the cell cycle in addition to myogenic gene induction via active chromatin formation coupled with transcription.